If it’s not clear after the inevitable Swedish-chef-muppet impression has run through your mind, this string-formatting operation will replace the contents of port with a string containing two copies of whatever was in port, separated by a colon. So if port was "foo", now it will be "foo:foo".

When you want to do scientific work in Python, the first library you can turn to is SciPy. As you’ll see in this tutorial, SciPy is not just a library, but a whole ecosystem of libraries that work together to help you accomplish complicated scientific tasks quickly and reliably.